ie: they formatted their OS drive, and installed Windows 10 on its own, without 'upgrading' a previously installed Windows version.
I say this, because i had this happen to me ONLY after doing the above. My Windows was having issues i couldnt figure out how to fix, so i did a clean whype/reinstall of my OS Drive. Then, while reinstalling all of my games (as my gaming Drive had died and needed replaced

Doing a bit of digging, i found out that this file is part of:
[color=#2F2F2F]Microsoft Visual C++ 2010 SP1 Redistributable Package (x64)[/color]
Which can be found here: https://www.microsof...s.aspx?id=13523
(if the page says it cant find the file, refresh a few times, it does exist, but MS's server sometimes cant pull it up on the first try)
Apparently MWO requires a C++ file that is only found in the 2010 version of MSVC++, and the 'install' version of Windows 10, only installs the new 2012 version of that software.
No amount of reinstalling MWO, or making sure Windows 10 is 'updated' will fix this if you do a 'clean' install of Windows 10, you MUST manually download and install the MSVC++ 2010 file to fix this issue.
Hope this helps anyone who runs into this Issue.
And PGI, ya may want to update your installer so that it adds this file on its own since windows apparently no-longer installs it itself. (at least windows 10 does not)